Magic
There are many dimensions to our world. There are four which we usually interact with: the three physical dimensions (width, height, and depth) plus the dimension of time, which allows for change in the other three dimensions. In this world, there is a fifth dimension, whose importance is slightly less noticeable, but whose power is just as real: the dimension of magic. The dimension of magic suffuses the world through its connections with the other dimensions. In some places and times, its connection grows stronger. Some objects or beings are also naturally infused with a strength of magic. Magic waxes and wanes, flickering and sliding in and out of prevalence across the world. It is a power of chaos and disorder; a world where the magical dimension was as strong as time or the physical dimensions would be a world entirely unrecognizable to us. Runes The humanoid races of the world currently have a very small connection to magic and its use. This connection is achieved through the use of runes. Runes are shapes or patterns which, when combined with a conscious intent, can allow magic to be wielded in the physical world. Millions of distinct runes exist, each discovered through chance, experimentation, or inter-dimensional shenanigans. Today, most runes have been long forgotten, though isolated scholars and occultic groups remember some runes. Larger lists of ancient runes are kept in some libraries, but most are not in use today; information about runes is often the target of fear-fuelled destructive missions, as the power offered by magic is enough to cause fear. One of the greatest treasures to be found in old ruins is a collection of ancient runes - once the common stock of an ancient civilization, but now worth all the fortunes of a noble. Runes need not be used by physical movements of the hand, though this is their most common use. Often, runes are inscribed in magically-infused objects or stones - usually with a specific trigger to set off their effects. Runes might also be applied to a scroll or staff and cast at will from their, but these items are liable to break after repeated use or produce unreliable or subpar effects. To use a rune requires a very precise recreation of the rune's pattern; thus, to actually have any effect with runes, a practitioner would require months - if not years - of frequent practice, combined with meditative efforts to form a mental connection with the magical dimension. This would allow for the 'conscious intent' portion of the arcane requirements to be sufficiently met. Runes are also very specific - there may be one rune for creating fire, and another for pushing it forward in a conical shape, while another module rune controls heat, one controls direction, and yet another manages the distance the cone can reach. Together, they could create a conical fire weapon that the user could control. Since runes are so difficult to come by, there are many limitations to what any individual user could accomplish based on the runes which they have mastered - however, these runes are also very multi-faceted. A 'conical shape' rune might be used in conjunction with fire creation, acid creation, poison creation, wind manipulation, sheer force, or water manipulation. Other runes might be specifically designed as triggers; for example, "When pressure applied, activate connected runes," or, "When magical presence appears in vicinity, activate connected runes," with another rune determining the area where pressure is measured or the vicinity which is monitored, respectively. In this way, runes offer many distinct options for application, although their practicality is limited by the difficulty of discovering and mastering them.